高分子质量聚L乳酸乙醇酸的制备及其性能

Preparation and characterization of high molecular weight poly(L-lactic-glycolic acid) copolymer

以六亚甲基二异氰酸酯(HDI)为扩链剂,对自制的双端羟基L乳酸乙醇酸预聚物(OLGA-OH)进行熔融扩链,进一步提高其分子质量。主要研究了HDI用量对扩链产物(PLGA)分子量及性能的影响。采用凝胶渗透色谱(GPC)、差示扫描量热(DSC)、热重分析(TGA)、傅里叶红外光谱(FT-IR)以及核磁共振谱(1H-NMR)对聚合物的相关结构与性能进行了表征。结果表明,当n(—NCO)∶n(—OH)=2∶1时,扩链效果最好,所得PLGA的分子质量最大,其数均分子质量和重均分子质量分别可达5.6×104和15.0×104,玻璃化转变温度亦由36℃提高到53℃。

High molecular weight poly（L-lactic-glycolic acid）（PLGA） was successfully synthesized by chain extension of hydroxyl terminated prepolymer（OLGA-OH） with 1,6-hexamethylene diisocyanate（HDI） as the chain extender.The impact of HDI dosage on the molecular weight and property of the chain extended product PLGA was investigated.The structure and properties were characterized using Fourier transform infrared spectroscopy（FT-IR）,gel permeation chromatography（GPC）,differential scanning calorimetry（DSC）,thermal gravimetric analysis（TGA） and nuclear magnetic resonance（NMR）.The results showed that the obtained PLGA appeared the best chain extension result and had the maximum molecular weight with Mn of 5.6×104 and Mw of 15.0×104 when n（—NCO）/n（—OH）=2∶1.The glass transition temperature of the PLGA was increased from 36 ℃ to 53 ℃ after chain extension.